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So on the switch, show run we need to configure additional configuration on these interfaces

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the switched virtual interfaces on the switch.

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We need to configure what's called an IP helper address to forward DHCP requests to the router.

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So there are a number of things we need to do on the switch including forwarding the DHCP request messages

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to the router.

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So let's do that on VLAN 10 and on VLAN 20.

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So firstly

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show run notice as per our diagram this interface is in VLAN 10 and this interface is in VLAN 20. So PC 1

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is in VLAN 10, PC 2 is in VLAN 20, and that's correct per the configuration shown here.

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Now that we've configured the IP addresses, DHCP requests will be forwarded to the router but the

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router needs to know about those networks.

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If a router receives a DHCP request from a network that it's not aware of, it won't allocate IP addresses.

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So on the router, I'm gonna create a static route pointing to the switch for network 10.1.10.0

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as well as 10.1.20.0.

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So at the moment now, the routing table contains those two static routes.

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In addition to the directly connected interfaces, so the router should be able to ping the switches

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switched virtual interfaces or SVIs, which it can. So the route rs able to ping this IP address as

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well as this IP address.

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Don't forget to add routes either using a dynamic routing protocol or something else so that you have

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IP connectivity in your network.

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We've been told that PCs need to be able to ping the loopback of router 1, router 1 has an IP address

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of 1.1.1.1 configured on the loopback.

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The switch doesn't know about that network. So we would have to add a static route

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or enable a routing protocol such as OSPF to allow the devices to ping each other.

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So now the switch can ping the loopback of the router.

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In this example, I'm using static routes, but you could have used a routing protocol such as OSPF

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or rip.

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Another thing we need to do on the switch is enable IP routing when traffic is sent from VLAN 10 to

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VLAN 20, the switch needs to do the inter VLAN routing of that traffic.

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So inter VLAN routing needs to be enabled by using the IP routing command. The switch needs to be  

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configured to route from one switched virtual interface to another.

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So hence we add the command IP routing to the switches configuration.

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So now let's test, are the PCs able to get IP addresses from the DHCP server and ping the loopback

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of the router. The first thing we need to do on the PC is ensure that it's using DHCP.

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And then we need to ensure that it's retrieved an IP address through DHCP, we can confirm that by using

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the command IP config.

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Notice in this example, it's retrieved an IP address of 10.1.10.1. Can it ping the switch?

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Yes, it can.

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Can it ping the router?

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Yes, it can.

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Can it ping the loopback of the router?

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Yes, it can.

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So that looks great.

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What about PC 2?

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We need to configure it to use DHCP, you can see here that it's already been allocated a gateway and

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DNS server.

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On the desktop, we can go to a command prompt and we can use the command IP config to verify whether

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it got an IP address through DHCP, it has. So, can it ping the default gateway, the switch?

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Yes, it can.

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Can it ping the routers Ethernet interface?

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Yes, it can. Can it ping the routers loopback address?

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Yes, it can.

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So that's looking great.

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What about the PCs pinging each other?

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So here's PC 1,

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here;s PC 2, IP address on PC 1 is 10.1.10.18

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ping 10.1.10.18, that works. I.P. address on this side is 10.1.20.13, so can PC

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1 ping 10.1.20.13?

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Yes, it can.

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So at this point, we've got the lab working.

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So can router 1 ping PC 2?

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Yes, it can.

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Can it ping PC 1?

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Yes, it can, we can use the command help to see available commands on the PC.

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One of those commands is Traceroute.

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So traceroute to the loopback of the router. Notice the traffic goes to the switch

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and then it goes to the router.

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Traceroute to the router

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same happens here.

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What happens if we trace to PC 2 from PC 1 trace goes via the switch, so I'm happy with that.

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We successfully configured the network.

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Don't forget to save your configuration when you finished with your lab.

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I always do that in the exam, just to be sure.

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I hope you found this video and lab useful.